3 ms·

Can you point out something that talks about macros in Clojure vs Common Lisp, or SBCL in particular?

spdegabrielle 9y ago
See https://clojure.org/about/lisp https://clojure.org/about/lisp for the relationship between clojure and other lisps. Variable capture is a problem with lisp macros that lisp and clojure programmers have tools and strategies to manage. A number or languages use hygienic macros to avoid the variable capture problem: Scheme, Racket, Dylan, Elixir, Rust, Julia & Perl 6 (which has hygienic AND unhygienic macros) Racket has more advanced macro facilities specifically aimed at making new languages languages and DSLs. Syntax-parse is very interesting in how it addresses the problem of error reporting with macros.
- shakna 9y ago
  > Scheme, Racket, Dylan, Elixir, Rust, Julia & Perl 6 (which has hygienic AND unhygienic macros) Just want to add that Racket, and most Schemes also support both hygienic and unhygienic macros, through defmacro. [0][1] Though, their use is heavily discouraged. (And it may be worth pointing out that Guile's defmacro is actually implemented using syntax-case, which is hygienic most of the time, but flexible enough to let you do madcap things. [2]). [0] https://docs.racket-lang.org/compatibility/defmacro.html https://docs.racket-lang.org/compatibility/defmacro.html [1] https://www.gnu.org/software/guile/manual/html_node/Defmacros.html https://www.gnu.org/software/guile/manual/html_node/Defmacro... [2] http://stackoverflow.com/a/19666120 http://stackoverflow.com/a/19666120
KirinDave 9y ago
Racket has hygenic template macros, which are quite nice. Common Lisp offers a whole bunch of machinery around macros and more types of macros (most famously symbol macros). Clojure picks the worst of all worlds by making reduced-power backtick macros, not stack tracing the macro output on failures, and then having a culture that discourages the use of macros.
- lemming 9y ago
  Do you know of any template based macro systems which are more powerful than syntax-rules, but without going to the other extreme of full turing completeness? As I understand it, syntax-rules doesn't even let you concatenate strings to create new identifiers - everything in the output must come verbatim from the input or the template.

See https://clojure.org/about/lisp https://clojure.org/about/lisp for the relationship between clojure and other lisps. Variable capture is a problem with lisp macros that lisp and clojure programmers have tools and strategies to manage. A number or languages use hygienic macros to avoid the variable capture problem: Scheme, Racket, Dylan, Elixir, Rust, Julia & Perl 6 (which has hygienic AND unhygienic macros) Racket has more advanced macro facilities specifically aimed at making new languages languages and DSLs. Syntax-parse is very interesting in how it addresses the problem of error reporting with macros.

shakna 9y ago
> Scheme, Racket, Dylan, Elixir, Rust, Julia & Perl 6 (which has hygienic AND unhygienic macros) Just want to add that Racket, and most Schemes also support both hygienic and unhygienic macros, through defmacro. [0][1] Though, their use is heavily discouraged. (And it may be worth pointing out that Guile's defmacro is actually implemented using syntax-case, which is hygienic most of the time, but flexible enough to let you do madcap things. [2]). [0] https://docs.racket-lang.org/compatibility/defmacro.html https://docs.racket-lang.org/compatibility/defmacro.html [1] https://www.gnu.org/software/guile/manual/html_node/Defmacros.html https://www.gnu.org/software/guile/manual/html_node/Defmacro... [2] http://stackoverflow.com/a/19666120 http://stackoverflow.com/a/19666120

KirinDave 9y ago

Racket has hygenic template macros, which are quite nice. Common Lisp offers a whole bunch of machinery around macros and more types of macros (most famously symbol macros). Clojure picks the worst of all worlds by making reduced-power backtick macros, not stack tracing the macro output on failures, and then having a culture that discourages the use of macros.

lemming 9y ago
Do you know of any template based macro systems which are more powerful than syntax-rules, but without going to the other extreme of full turing completeness? As I understand it, syntax-rules doesn't even let you concatenate strings to create new identifiers - everything in the output must come verbatim from the input or the template.